The present invention relates to a loader for a printer for printing, preferably by thermal transfer, flat articles such as cards, in particular of plastic material, as well as a printer for printing, preferably by thermal transfer, provided with such a loader.
It relates more particularly to a loader for a printer of the type comprising, from upstream to downstream, a loader of articles to be printed adapted to coact with a drive element for ejecting articles from the loader, a printing device and transfer means to lead the articles sequentially from the outlet of the loader to the printing device and from the printing device to means for collecting printed articles. Such printers are well known to those skilled in this art.
Until now, the expulsion of a card contained in a loader in the direction of the printer takes place as follows. The loader is constituted by a housing connected to one of the surfaces of the body of the printer. This housing comprises, in its bottom wall, an opening. The cards, stacked within the loader, are held bearing against the bottom of the housing by a weight positioned on the uppermost card in the stack. A cylinder projects partially through the opening and comes to bear against said cards. This cylinder is driven in rotation by a motor to effect by friction the expulsion of a card from the housing of the loader. This motor is stopped as soon as the card is left which is then driven to within the printer by transport rollers driven in rotation by means of a second motor. The printing device, disposed within the printer, is itself controlled in operation by means of a third motor.
The use of a weight, simply disposed on the top of the stack of cards, generates a certain number of drawbacks. Thus, in the course of microvibrations undergone by the stack of cards during expulsion of a card from the loader, there will be a movement of the weight on the upper surface of the stack of cards, such that the weight becomes rapidly ineffective. Moreover, as this weight is simply connected to the interior of the loader by the user after loading the loader with cards, it frequently happens that the user forgets to place the weight within the loader.
In another embodiment that is also known, the loader is provided with a pivoting flap disposed within the loader, this flap being returned to bear against the top of the pile of cards by return means generally constituted by a spring. This spring permits exerting a pressure force on the stack of cards to permit pressing the stack of cards against the output motor element for the articles to be printed in the printer. This solution again is not entirely satisfactory. Thus, when the loader is full, the spring is strongly compressed. There results an excessive application of force on the stack of cards, adapted to give rise to wedging of the cards or the expulsion of several cards at once. Conversely, when the loader is almost empty, the spring is in its extended position and exerts a small bearing force on the flap, generating insufficient coaction of the flap with the expulsion motor member for the cards of the loader. The drawback of such a device inherent in its design results from the fact that the force exerted on the stack of cards by the spring is a variable force. The absence of a constant force gives rise to the mentioned drawbacks.
An object of the present invention is to provide a loader for a printer for the printing, preferably by thermal transfer, of the mentioned type, whose design of the bearing means against the stack of cards permits exerting a constant bearing force independently of the height of the stack of articles contained in said loader.
Another object of the present invention is to provide a loader of the mentioned type whose design permits optimizing, in the course of emptying the loader, the positioning of the point of bearing as a function of the height of the stack of articles to be discharged from the loader.
To this end, the invention has for its object a loader for a printer that prints, preferably by thermal transfer, flat articles such as cards, in particular of plastic material, this loader, which delimits a storage magazine of the cards in the stacked position being provided internally with a pivoting member, such as a pivoting flap, arranged to maintain, in the active position of the loader, the articles to be printed in bearing contact against a drive element for discharging the articles to be printed by means of an opening provided in a wall of the magazine, characterized in that the pivoting member is provided with a counterweight to form an assembly exerting a substantially constant bearing force on the article or articles to be printed, independently of the height of the stack, this pressure positioning itself in the course of emptying the loader by moving along one of the articles to be printed in a direction generally opposite the direction of expulsion of the articles from the loader.
The design of the pressure means of the loader against the stack of articles constituted by a pivoting member provided with a counterweight, the assembly being secured to the magazine of the loader so as to generate a bearing point that is self-positioning in the course of emptying the loader, permits obtaining, on the one hand, the exertion of a constant bearing force on said stack of cards, on the other hand an optimization of the positioning of the bearing point in the course of emptying the loader.
There results in particular the possibility of obtaining, when the loader is almost empty, a positioning of the bearing point such that it generates no raising of the articles, which phenomenon is observed in particular when the bearing point is near the leading end of or the rear end of the articles to be expelled from the loader.
The invention also has for its object a printer for printing preferably by thermal transfer flat articles such as cards, in particular of plastic material, said printer being provided with a loader for articles to be printed, characterized in that the loader is of the mentioned type.